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Lucas123 writes "In what is likely to be a strong rival to NAND flash memory, IBM today announced it has been able to successfully store more than one bit of data per cell in a more stable non-volatile memory called phase-change memory (PCM). Unlike NAND, Previously, PCM couldn't contend with flash because of its low capacity points. PCM does not require that data be erased before new data is written to it, which reduces write amplification or wear out and it has 100 times the write performance of flash. IBM researchers say they plan to license the technology to memory manufacturers instead of producing it themselves."

The problem with flash memory is that it is inherently volatile. It is based off the storage of a static charge, and there is no such thing as a perfect insulator. During normal operation, you need a high current to tunnel through the insulator and store the charge, but that charge will slowly leak out on its own over time. Given enough time, the charge will drop below a threshold and be read incorrectly.

All microprocessor technologies suffer from this to some extent, and CPUs are expected to hit a wall dealing with this leakage in about 15 years. Flash memory is only expected to get one or two more process shrinks before this leakage is expected to cause problems on a useful time frame. At this point, flash memory will have to be refreshed like traditional DRAM more and more frequently. Online SSDs can afford this, but offline USB drives cannot. Now you can simply start stacking chips, but your costs will rise geometrically, and heat dissipation will become a problem. Flash will be unable to produce higher capacity at lower prices.

One of these new technologies will pan out in the near term, because with the current technology reaching the end of its life, the industry will have to transition to something new to continue to sell new product.

On one system we stored programs by wiring them into a ROM. By hand. One wire per word, wrapped around the center pole of the E-cores clockwise for a 1, or counterclockwise for a 0. Then solder one end of the wire to the correct X address, and the other end to the correct Y address. Total, 256 16-bit words per board (Z was decoded to board-select).